Diagnostic apparatus such as endoscopes, are conventionally known and used for medical purposes. Typically, an elongated tubular or other shaped instrument body includes a insertion portion having viewing optics contained therein for allowing inspection of a subject of interest.
Among such known devices are intraoral dental cameras having a micro-video camera retained within the distal head of an elongated instrument body sized for insertion into the mouth of a patient. The micro-video camera includes a viewing lens portion which focuses an optical image onto a solid-state imager, such as a CMOS or CCD. An electrical signal is then relayed to processing circuitry which converts the signal into a monitor-ready video signal further relayed to a video monitor or other processing apparatus for providing real-time diagnostic analysis.
There is a specific and urgent need to provide a clean and sterile camera surface to the patient for prudent medical reasons. This need is heightened because there is typically bleeding in even the most routine of dental procedures, by which transmission of Hepatitis B, AIDS, etc, might occur if the instrument is not properly handled between patients. Because of the design of the instrument, it is preferable that the camera head. as well as the tubular instrument body, be properly cleaned due to the proximity to the mouth of the patient.
Sterilization is an option in which the instrument is dipped in a liquid bath containing a sterilization agent. Application of heat using an oven or other specialized apparatus is still another option. Each of the above techniques among others, however, is time-consuming and may also affect the useful life of the instrument, which contains sensitive electronics and optics. Therefore, a protective flexible sheath, made from polyethylene or other suitable material, such as described in U.S. Pat. No. 4,757,381, has been developed which is sized to encase the tubular instrument body, including the distal camera head. The sheath includes a transparent viewing window to allow the lens portion of the camera to adequately view the subject area after the sheath has been applied.
In use, however, dentists or hygienists using the intraoral camera are required to grip the sheathed tubular instrument body in order to then inspect areas of a patient's mouth. Due to the loose fitting of the sheath to the instrument body, there are instances in which the sheath or the instrument is twisted, making support of the instrument difficult and invariably causing the viewing window of the sheath to be shifted from the field of view of the lens portion of the camera, producing unfavorable results.
The aforementioned '381 patent attempts to correct this problem in a number of ways, including heat shrinking a portion of the sheath to tighten the fit of the sheath onto the camera head. Alternative methods include applying a vacuum to the sheath or using fluid pressure to control the positioning of the sheath window in the vicinity of the camera lens. None of these methods are particularly convenient, nor do they aid in providing support for the user of the instrument.
The above stated problems are competing in a sense, in that use of a fixedly attached handle would ease in support of the instrument, but would not be acceptable for allowing easy removal and replacement of the protective sheath after each patient use.
Therefore, there is a need to provide an intraoral dental camera which uses the flexible protective sheath in a manner which allows easy attachment and removal of the sheath, but which allows the instrument to be supportable without twisting of the sheath member.